1. Field of the Invention
The present invention relates to an in-mold gate opening and closing mechanism and a metal mold for injection molding.
2. Description of the Prior Art
Briefly speaking, a method for injection molding of synthetic resin is carried out by a cycle of picking up a solidified molded article from a metal mold by opening the metal mold (mold opening) after tightening an upper mold (fixed die or female die) and a lower mold (movable die or male die), filling the metal mold with melted synthetic resin, and cooling the same. At this time, since the molded article is provided with a resin part, a so-called xe2x80x9cspool runner gatexe2x80x9d, it is necessary to cut off the resin part by a certain method.
As a classical method, the gate portion (resin part) is cut off by cutting pliers, etc., various types of in-mold gate opening and closing mechanisms have been proposed and carried out as technical objects of improvement in production efficiency, a lowering of production costs, improvement in aesthetic evaluation, etc.
As an in-mold gate opening and closing mechanism, a system in which a gate opening and closing pin incorporated in advance in a mold is moved in line with opening movement of the mold, and is operated to the gate portion by an exclusively attached fluid pressure means, and the gate portion is cut off, a system in which the gate opening and closing pin is actuated by movement of a movable mold when opening the mold, and a tunnel gate system have been publicly known.
Since a conventionally known in-mold gate opening and closing mechanism is constructed so that a gate opening and closing pin is actuated in line with movement of an exclusively attached fluid pressure means and a movable mold, the mechanism is large-sized and complicated. Also, in the former system, a process to open and close a gate when opening the mold is required, and a loss in time is produced to carry out the process (cf. Japanese Patent No. 2966707).
In a case of multi-gate molding or molding to produce a plurality of articles, the number of gates is increased, and positioning of the gates becomes cumbersome. Therefore, in an in-mold gate opening and closing mechanism of the conventional system, there is a difficulty or a problem in that design and production of metal molds become complicated and increase costs.
Further, in the in-mold gate opening and closing mechanism of the conventional system, there is another shortcoming in that an aesthetic cut surface cannot be obtained because the gate portions are cut off after resin is hardened.
In view of the above-described problems and shortcomings, it is therefore an object of the invention to provide an in-mold gate opening and closing mechanism, whose structure is compact and simple, capable of facilitating incorporation of a cold runner die, a hot runner die, etc., into a mold and adjustment of gate balance, and a metal mold for injection molding.
The in-mold gate opening and closing mechanism and metal mold for injection molding according to the present invention is featured in the following construction:
1. (Refer to FIGS. 1xcx9c10 and 15xcx9c29) An in-mold gate opening and closing mechanism constructed so that a gate pin disposed at a gate in a mold is moved on the basis of resin pressure in the gate, in which the gate is opened by the gate pin escaping from the gate when the resin pressure exceeds an appointed pressure level when filling resin, and the gate is closed by the gate pin moving the gate direction when the resin pressure is lowered from the appointed pressure level when a filling of the resin is completed, wherein a void for a gate is provided at the upper end part of a base body, a guide groove is provided continuously from the gate void, and a gate pin is disposed therein; the corresponding gate pin is pressed in the direction of the above-described gate void by a spring disposed in the above-described base body, and a mechanism for adjusting spring pressure of the corresponding spring is provided; the corresponding gate pin escapes from the gate when the resin pressure exceeds a pressing force of the spring, which is adjusted by a mechanism for adjusting the spring pressure when filling resin to open the gate; and the above-described gate pin is moved in the gate direction by a pressing force of the spring adjusted by the mechanism for adjusting the above-described spring pressure when the resin pressure is lowered below an appointed pressure level after a filling of the resin is completed.
2. (Refer to FIG. 1) An in-mold gate opening and closing mechanism, in which one unit having the following component elements (A), (B) and (C) incorporated on the surface and in an inner space of the base body consisting of a metallic block is formed and incorporated in a metal mold, and a runner gate is opened and closed from the direction orthogonal to or the same direction as the direction of the gate.
(A) A gate void is formed at the upper end portion of a base body, and a gate pin is disposed in a guide groove provided continuously from the gate void.
(B) A columnar space is provided at the lower part of the above-described gate void inside the above-described base body, a spring and a moving cylinder in which the spring is accommodated are inserted into the columnar space, and the lower end of the above-described gate pin is engaged with and fixed at the rear end of the moving cylinder, wherein the above-described gate pin is always pressed in the direction of the gate void by a force of the above-described spring.
(C) A spring pressure adjusting nut that presses the rear end of the above-described spring is provided in a screwed-in state so as to turn clockwise and counterclockwise at the open end side of the above-described moving cylinder of the base body, wherein a pressing force acting on the gate pin can be increased by turning the corresponding spring pressure adjusting nut in the direction of contraction of the spring, and the pressing force acting on the gate pin can be decreased by turning the adjusting nut in the reverse direction of the corresponding turning direction.
3. (Refer to FIGS. 2 and 3) An in-mold gate opening and closing mechanism, in which one unit having the following component elements (A), (B) and (C) incorporated on the surface and in an inner space of the base body consisting of a metallic block is formed and incorporated in a metal mold, and a runner gate is opened and closed from the direction orthogonal to or the same direction as the direction of the gate.
(A) A gate void is formed at the upper end portion of a base body, and a gate pin is disposed in a guide groove provided continuously from the gate void.
(B) A columnar space is provided at the lower part of the above-described gate void inside the above-described base body, and a moving cylinder is inserted into the corresponding columnar space, a center shaft, which is inserted into the spring, is accommodated in the corresponding moving cylinder, and the lower end of the above-described gate pin is engaged with and fixed at the rear end of the moving cylinder, wherein the above-described gate pin is always pressed in the direction of the gate void by a force of the above-described spring.
(C) A center shaft is provided between a bearing hole prepared at the tip end side of the above-described base body and a bearing member that presses the rear end of the above-described spring that is fixed in a columnar hole at the rear end side of the base body, the above-described moving cylinder and spring are disposed at the corresponding center shaft, a stop bushing and a worm wheel are further disposed thereat, and the corresponding worm wheel is engaged with a rotatable worm, wherein as the corresponding worm is rotated, the above-described worm wheel that is interlocked with the corresponding worm is rotated, the pressing force of the spring is adjusted by the center shaft moving in the direction of tightening the spring by clockwise rotation on the basis of engagement with a bearing member by a screw mechanism or moving in the direction of opening the spring by counterclockwise rotation.
4. (Refer to FIGS. 5 through 7) An in-mold gate opening and closing mechanism in which a flange portion having an upper surface portion, which is flush with the upper surface portion of the corresponding metal mold when being incorporated in the above-described metal mold, is provided on the upper part of a base body consisting of a metallic block, one unit having the following component elements (A), (B), (C) and (D) incorporated therein is formed on the upper part surface of the base body and in the inner space at the lower part thereof and is incorporated in the metal mold, and a runner gate is opened and closed in the direction orthogonal to the gate direction or in the same direction as the gate direction.
(A) A gate void is formed at the end portion on the upper surface of the base body, and a gate pin is disposed in a guide groove that is provided continuously from the gate void.
(B) A columnar space is provided at the lower part of the above-described gate void inside the above-described base body, and a moving cylinder is inserted into the corresponding columnar space, a center shaft, which is inserted into the spring, is accommodated in the corresponding moving cylinder, and the lower end of the above-described gate pin is engaged with and fixed at the rear end of the moving cylinder, wherein the above-described gate pin is always pressed in the direction of the gate void by a force of the above-described spring.
(C) The above-described center shaft is provided with a gear, in which the corresponding center shaft is made into a rotation axis thereof, at an upper part thereof, a spring receiver nut that presses the rear end of the above-described spring is provided in a screwed-in state so as not to rotate at a portion where the corresponding center shaft is positioned downward toward the columnar space, and the lower end thereof is pivotally supported in a bearing hole at the bottom of the base body.
(D) A spring pressure adjusting nut is provided at the upper surface side of the above-described base body so that the nut can turn clockwise and counterclockwise, a gear that is provided at the lower part of the corresponding spring pressure adjusting nut rotates along with a rotation operation of the corresponding spring pressure adjusting nut, the center shaft rotates by rotation of the gear in which the above-described center shaft engaged with the corresponding gear is made into an axis, and a spring receiving nut that is provided so as not to rotate in accordance with rotation of the corresponding center shaft is moved in the axial direction of the center shaft, wherein the pressing force of the spring is adjusted.
5. (Refer to FIGS. 8 through 10) An in-mold gate opening and closing mechanism in which a flange portion having an upper surface portion, which is flush with the upper surface portion of the corresponding metal mold when being incorporated in the above-described metal mold, is provided on the upper part of a base body consisting of a metallic block, one unit having the following component elements (A), (B), (C) and (D) incorporated therein is formed on the upper part surface of the base body and in the inner space at the lower part thereof and is incorporated in the metal mold, and a runner gate is opened and closed in the direction orthogonal to the gate direction or in the same direction as the gate direction.
(A) A gate void is formed at the end portion on the upper surface of the base body, and a gate pin is disposed in a guide groove that is provided continuously from the gate void.
(B) A columnar space is provided at the lower part of the above-described gate void inside the above-described base body, and a moving cylinder is inserted into the corresponding columnar space, a center shaft, which is inserted into the spring, is accommodated in the corresponding moving cylinder, and the lower end of the above-described gate pin is engaged with and fixed at the rear end of the moving cylinder, wherein the above-described gate pin is always pressed in the direction of the gate void by a force of the above-described spring.
(C) A spring receiving nut that presses the rear end of the above-described spring is provided at the portion where the center shaft is positioned downward toward the columnar space, and the lower end of the center shaft is pivotally supported in a bearing hole at the bottom portion of the base body.
(D) The center shaft is rotated at the bearing shaft that is a hole drilled at the lower part of the above-described base body, and the above-described spring receiving nut is provided so as to move, wherein the pressing force of the spring is adjusted.
6. (Refer to FIGS. 15 through 18) An in-mold gate opening and closing mechanism in which one unit having the following component elements (A), (B), (C), (D) and (E) incorporated therein is formed on the upper surface of a base body consisting of a metallic block and in the inner space at the lower part thereof, and is incorporated in a metal mold, wherein a runner gate is opened and closed in the direction orthogonal to the gate direction or in the same direction as the gate direction.
(A) A gate void is formed at the end portion on the upper surface of the base body, and a gate pin is disposed in a guide groove that is provided continuously from the gate void.
(B) A columnar space is provided at the lower part of the above-described gate void inside the above-described base body, and a moving cylinder is inserted into the corresponding columnar space, a center shaft, which is inserted into the spring, is accommodated in the corresponding moving cylinder, and the lower end of the above-described gate pin is engaged with and fixed at the rear end of the moving cylinder, wherein the above-described gate pin is always pressed in the direction of the gate void by a force of the above-described spring.
(C) The above-described center shaft is provided with a gear, in which the corresponding center shaft is made into a rotation axis, at the upper part thereof, and the downward tip end thereof is inserted into the through-hole portion of an adjusting member, which presses the rear end of the above-described spring, slidably in the axial direction.
(D) The above-described adjusting member is attached to the lower part of the base body in a screwed-in state, and a stopper portion that adjusts the amount of movement with respect to an escape action of the gate pin by limiting the maximum moving position by being brought into contact with the lower end of the moving cylinder is provided at the outer circumference of the corresponding adjusting member.
(E) A spring pressure adjusting nut is provided on the upper surface side of the above-described base body so that the spring pressure adjusting nut can rotate clockwise and counterclockwise, a gear that is provided at the lower part of the corresponding spring pressure adjusting nut rotates along with rotation operations of the corresponding spring pressure adjusting nut, the center shaft rotates by rotation of the gear in which the above-described center shaft engaged with the corresponding gear is made into an axis, the above-described adjusting member moves in the axial direction by rotations together with the center shaft by rotations of the corresponding shaft, wherein the pressing force of the spring is adjusted.
7. An in-mold gate opening and closing mechanism in which one unit having the following component elements (A), (B), (C) and (D) incorporated therein is formed on the surface of the upper part of a base body consisting of a metallic block and in the inner space at the lower part thereof, and is incorporated in a metallic mold, and a runner gate is opened and closed in the direction orthogonal to the gate direction and in the same direction as the gate direction.
(A) A gate void is formed at the end portion on the upper surface of the base body, and a gate pin is disposed in a guide groove that is provided continuously from the gate void.
(B) A columnar space is provided at the lower part of the above-described gate void inside the above-described base body, and a moving cylinder is inserted into the corresponding columnar space, a center shaft, which is inserted into the spring, is accommodated in the corresponding moving cylinder, and the lower end of the above-described gate pin is engaged with and fixed at the rear end of the moving cylinder, wherein the above-described gate pin is always pressed in the direction of the gate void by a force of the above-described spring.
(C) The tip end portion downward of the center shaft is inserted into the through-hole portion of an adjusting member, which presses the rear end of the above-described spring, slidably in the axial direction, and simultaneously, the adjusting member is attached to the lower part of the base body in a screwed-in state, and a stopper portion that adjusts the amount of movement with respect to an escape action of the gate pin by limiting the maximum moving position by being brought into contact with the lower end of the moving cylinder is provided at the outer circumference of the corresponding adjusting member.
(D) The center shaft is rotated at the bearing hole that is a hole drilled at the lower part of the above-described base body, and the above-described adjusting member is moved in the axial direction to adjust the pressing force of the spring.
8. (Refer to FIGS. 19 through 23) An in-mold gate opening and closing mechanism in which one unit having the following component elements (A), (B), (C) and (D) incorporated therein is formed on the surface of the upper part of a base body consisting of a metallic block and in the inner space at the lower part thereof, and is incorporated in a metallic mold, and a runner gate is opened and closed in the direction orthogonal to the gate direction and in the same direction as the gate direction.
(A) A gate void is formed at the end portion on the upper surface of the base body, and a gate pin is disposed in a guide groove that is provided continuously from the gate void.
(B) A columnar space is provided at the lower part of the above-described gate void inside the above-described base body, and a center shaft that is inserted into the spring is accommodated in the corresponding columnar space, the lower end of the above-described gate pin is engaged with and fixed at the upper part of the center shaft, and the above-described gate pin is always pressed in the direction of the gate void by a force of the above-described spring.
(C) An adjusting member that presses the rear end of the above-described spring is fitted to the lower part of the center shaft, and at the same time, to the downward inner side at the lower part of the base body in a screwed-in state, the adjusting member is rotated from the bottom part of the above-described base body, and the adjusting member moves in the axial direction of the center shaft while rotating, wherein the pressing force of the spring is adjusted.
(D) A stopper plane that adjusts the amount of movement with respect to an escape action of the gate pin by limiting the maximum moving position by being brought into contact with the lower end of the center shaft is provided inside the corresponding adjusting member.
9. (Refer to FIGS. 24 through 27) An in-mold gate opening and closing mechanism, in which the lower part of a base body consisting of a metallic block is movably provided in the direction of rotation with respect to the upper part of the base body consisting of a metallic block, one unit having the following component elements (A), (B), (C) and (D) incorporated on the upper surface of the base body and in the inner space at the lower part thereof and is incorporated in the metallic mold, wherein a runner gate is opened and closed in the direction orthogonal to the gate direction or in the same direction as the gate direction.
(A) A gate void is formed at the end portion on the upper surface of the base body, and a gate pin is disposed in a guide groove that is provided continuously from the gate void.
(B) A columnar space is provided at the lower part of the above-described gate void inside the above-described base body, and a center shaft that is inserted into the spring is accommodated in the corresponding columnar space, the lower end of the above-described gate pin is engaged with and fixed at the upper part of the center shaft, and the above-described gate pin is always pressed in the direction of the gate void by a force of the above-described spring.
(C) An adjusting member that presses the rear end of the above-described spring is fitted to the lower part of the center shaft, and at the same time, to the downward inner side at the lower part of the base body in a screwed-in state, the adjusting member is rotated from the bottom part of the above-described base body, and the adjusting member moves in only the axial direction without rotating, wherein the pressing force of the spring is adjusted.
(D) A stopper plane that adjusts the amount of movement with respect to an escape action of the gate pin by limiting the maximum moving position by being brought into contact with the lower end of the center shaft is provided at the inner side portion of the corresponding adjusting member.
10. (Refer to FIGS. 28 and 29) An in-mold gate opening and closing mechanism in which the lower part of a base body consisting of a metallic block is provided so as to be movable in the direction of rotation with respect to the upper part of the base body consisting of a metallic block, one unit having the following component elements (A), (B), (C), (D) and (E) incorporated on the surface of the upper part of the base body and in the inner space at the lower part thereof, and is incorporated in a mold, wherein a runner gate is opened and closed in the direction orthogonal to the gate direction or in the same direction as the gate direction.
(A) A gate void is formed at the end portion on the upper surface of the base body, and a gate pin is disposed in a guide groove that is provided continuously from the gate void.
(B) A columnar space is provided at the lower part of the above-described gate void inside the above-described base body, and a center shaft that is inserted into the spring is accommodated in the corresponding columnar space, the lower end of the above-described gate pin is engaged with and fixed at the upper part of the center shaft, and the above-described gate pin is always pressed in the direction of the gate void by a force of the above-described spring.
(C) The upper end portion at the lower part of the above-described base body is formed to be like a gear, a gear mechanism that is engaged with the corresponding gear-like upper end portion is provided in the upper part of the above-described base body, and an adjusting nut of said gear mechanism is provided on the upper surface at the upper part of the base body.
(D) An adjusting member is fitted downward of the center shaft, and at the same time, to the downward inner side at the lower part of the base body in a screwed-in state, the lower part of the base body is rotated by rotation operations of the adjusting nut, and the adjusting member moves in only the axial direction without rotating, wherein the pressing force of the spring is adjusted.
(E) A stopper plane that adjusts the amount of movement with respect to an escape action of the gate pin by limiting the maximum moving position by being brought into contact with the lower end of the center shaft is provided at the inner side portion of the corresponding adjusting member.
11. (Refer to FIG. 20) The in-mold gate opening and closing apparatus as set forth in any one of the above-described points 6 through 10, wherein the lower part of the base body is cylindrical.
12. (Refer to FIGS. 5 through 29) An in-mold gate opening and closing apparatus as set forth in the above-described points 1 through 11, wherein a flange portion having an upper surface portion that is flush with the upper surface portion of a mold at a portion that incorporates the corresponding in-mold gate opening and closing apparatus is provided on the upper part of the above-described base body.
13. (Refer to FIGS. 16 through 18, 21 through 23 and 25 through 27) An in-mold gate opening and closing apparatus as set forth in any one of the above-described points 1 through 12, wherein the amount of movement of an escape action of the above-described gate pin is adjusted step-free from full opening to full closing of the gate.
14. (Refer to Drawings A and C of FIG. 30) An in-mold gate opening and closing apparatus as set forth in the above-described points 1 through 13, wherein the tip end shape of the above-described gate pin is formed of at least two planes, one of which is a horizontal plane roughly orthogonal to the moving direction of the corresponding gate pin and the other of which is a pressure receiving plane consisting of an inclined plane obliquely crossing the moving direction thereof.
15. (Refer Drawings B and C of FIG. 30) An in-mold gate opening and closing apparatus as set forth in the above-described points 1 through 13, wherein the tip end shape of the above-described gate pin is formed of only a pressure receiving plane consisting of an inclined plane obliquely crossing the moving direction of the corresponding gate pin.
16. (Refer to Drawings C and D of FIG. 30) An in-mold gate opening and closing apparatus as set forth in the above point 14 or 15, wherein the pressure receiving plane consisting of an inclined plane at the tip end of the above-described gate pin is formed to be concavely curved.
17. (Refer to FIG. 4 and FIGS. 11 through 14) A mold for injection molding, which is provided with an in-mold gate opening and closing apparatus as set forth in any one of the above-described points 1 through 16.
18. (Refer to FIG. 31) A mold for injection molding as set forth in the above-described point 17, wherein the end portion at the tip end of the gate pin of the in-mold gate opening and closing apparatus is disposed so that the end portion is not caught by the PL plane when the gate is closed.